package com.retailshop.shopuser.common;

import com.alibaba.fastjson.JSONObject;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.retailshop.shopuser.entity.UserNo;

import com.retailshop.shopuser.service.UserNoService;


import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.lang.reflect.Method;

public class AuthenticationInterceptor  implements HandlerInterceptor {


    private UserNoService userNoService;
    public AuthenticationInterceptor(UserNoService userNoService){
        this.userNoService=userNoService;
    }

    @Override
    public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object object) throws Exception {
        String token = httpServletRequest.getHeader("token");// 从 http 请求头中取出 token
        // 如果不是映射到方法直接通过
        if(!(object instanceof HandlerMethod)){
            return true;
        }
        HandlerMethod handlerMethod=(HandlerMethod)object;
        Method method=handlerMethod.getMethod();
        //检查是否有passtoken注释，有则跳过认证
        if (method.isAnnotationPresent(PassToken.class)) {
            PassToken passToken = method.getAnnotation(PassToken.class);
            if (passToken.required()) {
                return true;
            }
        }
        //检查有没有需要用户权限的注解
        if (method.isAnnotationPresent(UserLoginToken.class)) {
            UserLoginToken userLoginToken = method.getAnnotation(UserLoginToken.class);
            if (userLoginToken.required()) {
                // 执行认证
                if (token == null) {
                    String jsonObjectStr = JSONObject.toJSONString(new Response(MessageConstants.TOKEN_UNEXIT, null, 0, "", httpServletRequest));
                    returnResult(httpServletResponse, jsonObjectStr);
                   return false;
                }
                // 获取 token 中的 user id
                String userId=null;
                try {
                    userId = JWT.decode(token).getAudience().get(0);
                } catch (JWTDecodeException j) {

                    String jsonObjectStr = JSONObject.toJSONString(new Response(MessageConstants.TOKEN_ERROR, null, 0, "", httpServletRequest));
                    returnResult(httpServletResponse, jsonObjectStr);
                }

                UserNo user =userNoService.selectByPrimaryKey(Integer.parseInt(userId));
                if (user == null) {
                    String jsonObjectStr = JSONObject.toJSONString(new Response(MessageConstants.MSG_USER_INEXISTENCE, null, 0, "", httpServletRequest));
                    returnResult(httpServletResponse, jsonObjectStr);
                    return false;
//
                }

                // 验证 token
                String str="xlsyear2019";
                JWTVerifier jwtVerifier = JWT.require(Algorithm.HMAC256(str)).build();
                try {
                    jwtVerifier.verify(token);
                } catch (JWTVerificationException e) {

                    String jsonObjectStr = JSONObject.toJSONString(new Response(MessageConstants.TOKEN_VERIFY, null, 0, "", httpServletRequest));
                    returnResult(httpServletResponse, jsonObjectStr);
                    e.printStackTrace();
                    return false;

                }
                return true;
            }
        }
        return true;
    }

    @Override
    public void postHandle(HttpServletRequest httpServletRequest,
                           HttpServletResponse httpServletResponse,
                           Object o, ModelAndView modelAndView) throws Exception {

    }
    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest,
                                HttpServletResponse httpServletResponse,
                                Object o, Exception e) throws Exception {
    }

    private void returnResult(HttpServletResponse response, String str) throws Exception {
        PrintWriter writer = null;
        response.setCharacterEncoding("UTF-8");
        response.setContentType("text/html; charset=utf-8");
        response.setHeader("Access-Control-Allow-Origin", "*");
        try {
            writer = response.getWriter();
            writer.print(str);

        } catch (IOException e) {

        } finally {
            if (writer != null)
                writer.close();
        }
    }


}
